The field of the invention is optical transmission cables.
One type of optical transmission cable consists of an outer portion having one or more sleeves and strength layers and a core consisting of one or more discrete bundles of optical fibers, the bundles henceforth called cable elements. The cable elements may be separated from each other and the outer portion of the cable by a filling compound.
The use of optical transmission cables as major trunk cables has been accepted for some years. The present need is for cost effective cable designs which allow a small number of fibers to be branched off at pedestals or the like to serve individual subscribers or groups of subscribers living on the same street.
If the cable contains a large number of fibers, a way must be found to distinguish among the various fibers. Since twelve colors are standardized by Bellcore, one way to discriminate among fibers by color is to have up to twelve fibers in each cable element and allow up to twelve cable elements in a cable. It would also be highly useful for the cable design to allow one or two fibers to be separated from a cable without destroying the functionality of a cable element.
Prior cable designs allow for the possibility of completely encasing optical fibers in a layer of plastic around a strength member. However, such a design does not allow for easy removal of optical transmission fibers from a cable. Designs which allow ease of removal will facilitate extension of the optical fiber network to individual subscribers.